JPS61196505A - Inductance structure - Google Patents

Abstract

PURPOSE:To enable to obtain a large inductance value with a small area by a method wherein a plurality of conductive fine strips are provided almost in parallel on one of plural layers, and said conductive fine strips are connected to other conductive wirings in such a manner that the current runs in the same direction. CONSTITUTION:A helical coil, having a magnetic core 4 in the center,is formed using the wiring pattern 1 formed on the first layer of conductor, the wiring pattern 2 formed on the third layer of conductive layer, the aperture 3 on the interlayer insulating film to be used to connect the first layer wiring 1 and the third layer wiring 2, and the magnetic core 4 of high permeability formed on the second layer. Accordingly, if a current runs in the direction of I, a magnetic flux is generated in the direction of phi, and as said magnetic flux phi is generated in the direction in parallel with magnetic core 4, the magnetic flux phican be enhanced by using the material having a high permeability for the magnetic core, thereby enabling to form the coil having a high self-inductance.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to an inductance structure, and particularly to an inductance structure using multilayer conductors.

[Conventional technology]

Conventionally, for inductance structures using conductors formed on a flat plate, there is a method in which the conductor is formed not parallel to the flat plate but in a wound shape, and the size of the inductance is adjusted by the number of turns.

[Problem that the invention seeks to solve]

However, in such an inductance formation method using a thinly wound structure, the rate of increase in the required area accelerates as the number of turns increases, and magnetic flux is generated in a direction perpendicular to the flat plate surface, so the magnetic core is used to increase the magnetic flux density. It has been difficult to effectively install the inductance on a flat plate, and it has been difficult to obtain a large inductance value due to these circumstances.

In order to eliminate these conventional drawbacks, the present invention aims to reduce the rate of increase in the required area as the number of turns increases, and to obtain a large inductance value in a smaller area by adopting a structure that allows the magnetic core to be inserted effectively. This will show you how it can be done.

[Failure to solve the problem]

That is, the method for forming an inductance according to the present invention has a plurality of conductor layers separated from each other by an insulating film, and it is possible to connect conductors in different layers by providing an opening in the insulating film at a desired position. In the multilayer flat plate, a plurality of conductor strips are provided substantially in parallel on at least one of the plurality of conductor layers, and these are connected to other conductor wiring so that current flows in the same direction. In this way, the direction of the magnetic flux coincides with the direction parallel to the substrate surface where it is easy to form the magnetic core, so it is easy to increase the generated magnetic flux density, and the number of turns, that is, the number of almost parallel conductor strips, can be increased. The increase and the increase in the required area have a linear relationship with each other, and the required area does not increase at an accelerated rate as the number of turns increases. That is, it is possible to obtain a larger inductance value in a smaller area than with the conventional structure.

〔Example〕

Next, the present invention will be explained with reference to figures of application examples.

FIG. 1 is a typical example to which the present invention is applied.

In FIG. 1, the dotted line indicates the wiring button 1 formed on the first layer conductor, 2 the wiring button 2 formed on the third conductor layer, and 3 the first layer wiring 1. It shows an opening in the interlayer insulating film for connecting with the third layer wiring 2, and in the same part,
As will be made clear later in FIG. A conductive layer formed in layers may be interposed. 4 is a magnetic core formed in the second layer and made of a material such as Ni or Fe having high magnetic permeability. In the figure, since the first layer wiring button and the third layer wiring button overlap each other in substantially the same shape at the opening 3, the dotted line indicating the first layer wiring is not drawn. Now, as is clear from the above explanation, FIG. 1 forms a helical coil having the magnetic core 4 at the center. Now, if a current flows in the direction of Φ in FIG. 1, a magnetic flux will be generated in the direction of Φ in FIG. The magnetic flux Φ occurs in a direction parallel to the layers of the magnetic core 4, so by applying a material with high magnetic permeability to the magnetic core 4, the magnetic flux Φ can be increased, resulting in a coil with high self-inductance. can be formed.

Figure 2 shows the cross-sectional structure taken along line A-B shown in Figure 1.
is a substrate, 2 is a wiring formed in the first conductive layer, 3 is an interlayer insulating film provided between the first conductive layer and the second layer, and 7 is a wiring formed in the third layer. Wiring formed in the conductor layer, 4 a magnetic core made of a material with high magnetic permeability formed in the second layer, 5
6 is a conductive layer that mediates the connection between the first layer wiring 2 and the third layer wiring 7 formed in the same layer in which the magnetic core 4 is formed; An interlayer insulating film provided between the conductor layer, 8 a protective film, and 9.10 an opening for connecting the first layer wiring 2 and the conductive layer 5, and the conductive layer 5 and the third layer wiring 7, respectively. Shows the hole. In Figure 2, 2.4.7 corresponds to 1.4.2 in Figure 1, and 9.1 in Figure 2
0 corresponds to FIG. 13.

In FIG. 2, the conductive layer 5 that mediates the connection is provided when necessary as already mentioned in the explanation of FIG. 1, but if the magnetic core 4 is made of a conductive material, In particular, in that case, in order to improve the adhesion and electrical contact between the first layer wiring and the third layer wiring in the openings 9 and 10 and the conductive layer 5. A thin layer made of a different material may be provided on the bottom and top surfaces of the conductive layer 5 (or both the conductive layer 5 and the magnetic core 4). Further, for the same purpose, a thin film similar to the above may be provided on the upper surface of the first layer wiring 2 or the lower surface of the third layer wiring 7. In particular, in this case, the thin film is formed in the openings 9 and 10. It may be provided only in the vicinity. Further, the substrate 1 may be a semiconductor substrate on which elements such as transistors and resistors are formed, and these may be connected to the inductance forming system according to the present invention to form a circuit. Furthermore, especially when the current introduced into the inductance forming part has a high frequency and a high inductance value is not required, or when noise generation due to the hysteresis characteristics of the magnetic core material is a problem, the magnetic core is It does not need to be installed. In this case, the third layer wiring 7 may be a wiring formed in the second layer, and in this case, the conductive layer 5 is clearly unnecessary.

FIG. 3 shows an example of the application of FIG. 1, especially in a case where the shape of the magnetic core is changed. In FIG. 3, 1 and 1' are the first layer wiring, 2 is the third layer wiring, 3 is an opening for connecting the first layer wiring R1b or 1' and the third layer wiring 2, and 4 is the second layer wiring. It is a magnetic core formed in layers. In particular, the application example shown in FIG. 3 differs from that shown in FIG. 1 in that the magnetic circuit is closed by lighting and by making the magnetic core in the shape of a Japanese character. By providing a magnetic closed circuit using a material with high magnetic permeability in this manner, the amount of leakage magnetic flux to the outside can be reduced, and the influence of noise on neighboring circuits due to electromagnetic induction can be reduced. When using a sun-shaped magnetic core in this way, the coil lead wire either strengthens or weakens the magnetic flux depending on whether it passes through the upper layer or the lower layer of the part where the magnetic core exists, but it also reduces the inductance. In order to increase the size, it is preferable to lay a lead wire on the side that strengthens it, and in the application example shown in Figure 3, in order to comply with this principle, the first layer wiring 1' passing through the bottom of the magnetic core becomes the lead wire of the coil. ing. In addition to using a sun-shaped magnetic core, there are various ways to close the magnetic circuit, such as a mouth-shaped core, a circular shape, and the method shown in FIG. 4.

Also, the wiring pattern forming the coil in Figure 3 is slightly different from that in Figure 1, but this does not mean that the coil formation is necessarily limited to the application example of Figure 1 (and Figure 3). What is shown in the figure is essentially a batan that allows more turns to be obtained with a smaller required area in order to obtain a larger inductance value. On the other hand, the cross-sectional structure and configuration of the application example shown in FIG. 3 are the same as those described for the application example shown in FIG. 1 using FIG.

Next, in FIG. 4, a large number of magnetic cores 4 shown in FIG. 3 are arranged in the vertical direction of FIG. show. FIG. 4 1 is the first layer wiring, 2 and τ are the third layer wiring, 3 is an opening for connecting the first layer wiring and the third layer wiring, 4 is a magnetic field formed in the second layer. It is the core. The cross-sectional structure of this application example is basically the same as that shown in FIG. 2, but what is particularly distinctive about the structure shown in FIG. 4 is the topological formation method of the coil. That is, the fourth
The electric current flowing into the main body through the third layer wiring 2 from the introduction part to the inductance forming system at the upper right side of the figure (indicated by the bold line arrow) first passes over the upper part of the magnetic core 4 and intersects with it. It immediately enters the first layer wiring through the opening and connects to the magnetic core 4.
When it passes through the bottom of the magnetic core 4 and intersects with it, it passes through the opening again to reach the third layer wiring, passes through the top of the magnetic core 4, and so on. The wiring that returns will be at a position adjacent to the wiring that has already passed, with the passing side (top surface being the bottom surface) with respect to the magnetic core 4 reversed, and if the adjacent wiring layer is the 3rd layer wiring, in the return route, it will be the 1st layer wiring. If the wiring is the first layer wiring, the third layer wiring is used.

And repeat this method over and over again. By doing so, the directions of the magnetomotive forces induced by the currents in adjacent wirings can be made to match regardless of the helical coil (hereinafter, such a coil shape will be referred to as one-screw spiral I). . On the other hand, in FIG. 4, as in the application example of FIG. 3, the magnetic core 4 meanderingly forms a series of closed rings in order to close the magnetic circuit.

FIG. 5 shows a schematic spatial image of the application example shown in FIG. 4. In FIG. 5, 1 indicates the conductor part of the coil, which is a series of conductive parts formed by the first layer wiring 1, the third layer wiring 2, and the opening part 3 in FIG. Corresponds to the road. Moreover, FIG. 5 2 shows the magnetic core,
This corresponds to the magnetic core 4 in FIG. The direction of the magnetic flux Φ generated when the electric current flows in the direction of the nine arrows shown in the conductor portion 1 of FIG. 5 is shown by the arrow drawn along the magnetic core 2.

Forming inductance using such a hexagonal helix l has a limit when using the layered conductor of the present invention, unlike ordinary electromagnets in which coils are stacked and wound in many layers around a magnetic core. It is from.

As already explained in the application example of Fig. 1, even in the application example of Fig. 4 (and Fig. 5), the magnetic core may not be installed depending on the case, and in that case, a two-layer wiring system may be used. An inductance forming body is completed, but in the application example shown in Figure 4, when the magnetic core is removed, the series connection of magnetomotive force, which had been dominant due to the difference in magnetic permeability with the outside of the magnetic core, breaks down and is As a result, the contribution of leakage magnetic flux to the whole becomes apparent, and as a result, the inductance value decreases by more than the decrease in magnetic permeability. However, if the magnetomotive force generating section is linear as in the application examples shown in FIGS. 1 and 3, this reduction effect can be suppressed to a fairly small degree.

FIG. 6 schematically shows another example of application of the present invention, where 1 indicates a conductive system and 2 indicates a magnetic core. When the electric current flows in the direction of the arrow marked on the conductor portion 1, a magnetic flux Φ is generated in the direction of the arrow marked along the magnetic core 2. The method of forming the conductive system 2 in the same figure is topologically the same as that in Figure 4 (or Figure 5), and relies on the twisted helix l, but it is not oriented parallel to the substrate plane. , is distinctive in that it is formed by multilayering in the vertical direction rather than in the vertical direction. Therefore, the magnetic core 2 is also multi-layered, and in this case, a shape as shown in FIG. 6 is used to close the magnetic circuit in a series-connected state to transfer the magnetomotive force. An example of concretely realizing the schematic diagram shown in FIG. 6 is shown in FIG.

In FIG. 7, 1 is a wiring batten formed in the first layer, 3 is a wiring batten formed in the third layer, and 2 is for connecting the first layer wiring and the third layer wiring. , 5 is a wiring batten formed in the fifth layer, 4 is an opening for connecting the third layer wiring and the fifth layer wiring, 7 is a wiring batten formed in the seventh layer, 6 is an opening for connecting the fifth layer wiring and the seventh layer wiring, 8 is a magnetic core pattern formed in the second layer, 10 is a hole in the fourth layer, and 12 is a hole in the sixth layer. In the formed magnetic core pattern, 9 is an opening for connecting the magnetic core 8 of the second layer and the magnetic core 10 of the fourth layer, and 11 is an opening for connecting each magnetic core of the fourth and sixth layers. It is an open hole. In the application example shown in Fig. 7, the holes 2, 4, 6 for connecting the wiring between layers and the holes 9 and 11 for connecting the magnetic cores between layers do not cause the difference in level that occurs at the hole portion. Although these holes are shown in a state where they are not overlapped at the same position, it is of course possible to drill them at the same position as long as there is no problem such as the above.

Now, since Figure 7 is complicated with many overlapping slams, a cross-sectional view taken along line C-D in Figure 7 is shown in Figure 8, and one twisted line l is thereby formed in the conductive system. Explain. In FIG. 8, 1 is the first layer wiring, 2
and 2' are openings for connecting the first layer wiring and the third layer wiring, 3 are the third layer wiring, 4 and 4' are openings for connecting the third layer wiring and the fifth layer wiring, 5 is the fifth layer wiring, 6 and 6' are openings for connecting the fifth layer wiring and the seventh layer wiring, and 7 is the seventh layer wiring.
Layer wiring, 8, 10.12 are magnetic cores formed in the second layer, fourth layer, and sixth layer, respectively, and are 1 to 12 and ? of the 8th layer described above. 4/ and 6/ correspond in content to the same numbers on CD in FIG. On the other hand, No. 8 13 is the board, 14 to 19 are 1 to 2 degrees, 2 to 3.3 degrees, respectively in numerical order.
~4,4~5.5~6,6~7 interlayer insulating film between layers, 20
is a surface protective film. Next, 21°22.23 are the first layer wiring and the third layer wiring, the third layer wiring and the fifth layer wiring, respectively.
5th layer wiring and 7th layer! This is a conductive layer that mediates connection with wiring. Now, in Fig. 8, the current flow path is the first layer wiring 1.
If you trace it further (hereinafter only the numbers in Figure 8): 2.21
．． 2'.

3, 4.22.4', 5.6.23. As shown in Fig. 7, the tip of the seventh layer wiring 7 connects to the adjacent fifth layer wiring through an interlayer hole, and its position is In this case, the cross-sectional structure of FIG. 8 is left and right reversed at the center, and connections are made to the third-layer wiring and the first-layer wiring in descending order. Further, as is clear from FIG. 7, the first layer wiring 1 is also connected to the adjacent third layer wiring, and is connected to the fifth layer wiring at that position to reach the outside from the inductance forming portion.

From the above explanation, it will be clear that in FIG. 7, the air-twisted helical current flow path surrounding the magnetic core shown in FIG. 6 is realized. On the other hand, to explain the magnetic circuit, in FIG.
The magnetic core 10 is connected to the magnetic core 10 formed in the fourth layer through a hole 9 (at the bottom of the figure), and the magnetic core 10 has a rectangular shape long from side to side. It is connected to the magnetic core 12 formed in layers. The magnetic core 12 has a katakana Y-shape, and is connected to the small rectangular magnetic core 10 by opening holes 11 at both the upper and lower ends on the left side, and then connecting it to the small rectangular magnetic core 10 through the opening 9. Both sides are connected to the upper and lower ends of the T-shape when it is tilted 90 degrees to the left. It is clear that a magnetic closed circuit is now completed, and it is also clear that the magnetomotive force is connected in series in the area surrounded by the conductor system. By the way, in the openings 9 and 11, it is necessary to make a magnetic connection, but this requires direct contact with the second
It is also possible to connect the magnetic cores of the fourth layer and the fourth layer, or the fourth layer and the sixth layer, or if this is done, the step of the opening becomes steep, causing problems such as breakage of the magnetic core material. In this case, a material with high magnetic permeability may be placed in the opening as an intermediate medium.

Further, although the magnetic resistance increases, it is also possible to leave no openings. However, in this case, the condition described below when no magnetic core is installed becomes somewhat dominant, and the inductance value decreases.

In Figure 7, the magnetic core may be omitted as in the previous application examples, but if you do this, the magnetomotive force can be measured in series for the same reason as explained in Figure 4. The magnetic circuit connected to t′! ! It almost disappears, and the inductance value becomes smaller than the decrease in magnetic permeability.

Now, using the same concept as the structure shown in FIG. 6, an inductance forming body can be made with any number of layers. This is schematically shown in FIGS. 9 and 10.

FIG. 9 (A), (B), (C) and (D) for cases where the magnetic core layer is one layer, two layers, three layers, and four layers, respectively,
It shows an example of the configuration of a twisted helix l and the configuration of a magnetic closed circuit of a magnetic core, where 1 is a conductive system and 2 is a magnetic core.

Figures 10 (A), (B), (C) and (D) are
Figures 9 (A), (B), (C) and (D), respectively.
) is a cross-sectional image of the inductance forming body corresponding to (
It is the same as that of B), (C), and (D). Especially 3
This shows that it is acceptable for a partially irregular one-twist helix I to have one jump I, in which the current direction coincides with the direction in which the magnetic flux is generated; in fact, it is formed in layers. In the coil shown in Fig. 9, the length in the vertical direction, that is, the thickness of the layer, is very short compared to the length in the horizontal direction.
Its contribution to inductance is very small.

It is clear from FIG. 9 that the same rules as in (A) to (D) can be applied to magnetic core layers having five or more layers. In addition, (A) is Fig. 3, and (C) is Fig. 6 (or Fig. 7).
It is the same as that of

In addition to the various application examples described above with reference to FIGS. 1 to 10, various forms can be considered. Although explanations using figures will be omitted below, for example, if the magnetic core is moved to the third layer and the second layer is
Double winding in which a helical coil is formed by the layer wiring and the fourth layer wiring, and then another helical coil is formed on top of that by the first layer wiring and the fifth layer wiring, and these are connected to each other. The coil or planar shape is a mouth shape or a circle, and a spiral coil is formed on all sides (or the entire circumference) of the magnetic core (7 types,
In order to form this in a direction perpendicular to the plane, magnetic cores are placed in the second and fifth layers, and both ends of the magnetic cores are magnetically connected to form a ring shape. A spiral coil is formed by the wiring and the third layer wiring, and a spiral coil is formed on the fifth layer magnetic core by the fourth layer wiring and the 6th-layer wiring, and these are connected in series, Furthermore, a partially helical shape or a one-twisted helical shape having a different diameter (in the present invention, the width on a plane in a direction perpendicular to the magnetic flux) can be considered as an application example of the present invention.

〔Effect of the invention〕

As is clear from the many application examples of the present invention described above, according to the inductance forming method according to the present invention, there is a linear relationship between an increase in the number of turns and an increase in the required area, and the inductance value Even if the number of turns is increased to increase the number of turns, the required area will not increase at an accelerated pace. In addition, since the magnetic flux is generated in a direction parallel to the substrate surface, it is possible to efficiently use a magnetic core that can be easily installed in a direction parallel to the substrate surface. Since it can be created easily, a magnetic core having a shape that allows magnetomotive force to be connected in series can be easily obtained, and furthermore, it can be deformed according to the circumstances around the pattern on the plane. Furthermore, whether or not to install a magnetic core can be freely selected depending on whether or not to form a magnetic core pattern. Further, by making the inductance forming body multilayered, it is possible to downsize the inductance forming body and increase the inductance value per fixed substrate area. Due to the various advantages described above, the present invention enables prizes to be provided with an inductance on an integrated circuit chip, which has rarely been done in the past. Moreover, since this pattern can be formed only by the wiring process on the integrated circuit chip, using multilayer wiring technology, transistors, diodes, resistors,
In addition, the inductance forming body according to the present invention can be made to share the chip surface with a diffused capacitor, etc. In particular, as mentioned above, the inductance forming body according to the present invention can be freely deformed in shape. It is also easy to adjust the plane space between patterns. That is, when the present invention is applied to an integrated circuit chip together with multilayer wiring technology, the degree of integration will not be hindered.

On the other hand, a discrete inductance device can also be obtained by configuring the inductance forming body according to the present invention on the entire surface of the substrate. This invention can be applied to fine print, and the effects of the present invention are extremely large.

[Brief explanation of drawings]

FIG. 1 is a plan view showing a typical application example of the present invention, in which 1 is a first layer wiring, 2 is a third layer wiring, and 3 is a first layer wiring and a third layer wiring.
Apertures 4 are provided for connecting layer wiring, and 4 is a magnetic core made of a material with high magnetic permeability provided in the second layer. Figure 2 shows the first
FIG. Both FIGS. 3 and 4 are plan views showing another example of application of the present invention. FIG. 5 is a diagram schematically representing the structure of FIG. 4 in a spatial image. 6th
The figure is a diagram schematically showing another application example of the present invention. FIG. 7 is a plan view that specifically realizes FIG. 6. FIG. 8 is a sectional view taken along line CD in FIG. 7. FIG. 9 is a diagram generally representing one application method of the present invention, and is a diagram (A) to (I).
)) is a schematic diagram with a spatial image, 1 represents a conductive system, 2 represents a magnetic core, and Figure 10 corresponds to Figure 7, and schematically represents a cross section in a plane perpendicular to the magnetic flux. This is a diagram. Agent Patent Attorney Susumu Uchihara ゝFigure 1 L'' Figure 5 Figure 4 - Figure 6

Claims (7)

[Claims] (1) Having multiple conductor layers separated from each other by insulating films,
In a multilayer flat plate in which conductors in different layers can be connected by forming holes in the insulating film at desired positions, a plurality of conductor strips are arranged in parallel in at least one of the plurality of conductor layers. , an inductance structure in which among the conductor strips, those having the same conductor layer are connected to other conductor layer wiring so that current flows in the same direction. (2) The inductance structure according to claim (1), characterized in that the conductor strips arranged in parallel are formed by intersecting plate-like pieces made of a material with high magnetic permeability, separated by layers. . (3) The conductor strips provided in the two conductor layers are connected to each other through an opening in an interlayer insulating film to form a helical coil.
The inductance structure described in section 2). (4) Conductor strips are interlayer insulated so that the direction of current flowing through conductor strips arranged in parallel in three or more conductor layers is opposite to each other between adjacent layers in which these conductor strips are provided. An inductance structure according to claim 1 or claim 2, wherein the inductance structure is connected through an opening in a membrane. (5) Claims (2), (3), or (4) characterized in that the plate-like piece made of a material with high magnetic permeability has at least one hollowed surface. Inductance structure described in section. (6) A patent claim characterized in that the plate-like pieces made of a material with high magnetic permeability provided in each of the plurality of layers are connected to each other through the openings of the interlayer film to form at least one annular shape. The inductance structure according to the range (2), (3), (4), or (5). (7) Claims (1) and (2), characterized in that the multilayer flat plate is made of an integrated circuit chip, and an inductance structure is connected to a circuit configured on the chip. The inductance structure according to item (3), item (4), item (5), or item (6).